36 Pa. Stat. § 652n
Any holder of bonds issued under the provisions of this act or any of the coupons attached thereto, and the trustee under the trust indenture, if any, except to the extent the rights herein given, may be restricted by resolution passed before the issuance of the bonds or by the trust indenture, may, either at law or in equity, by suit, action, mandamus or other proceedings, protect and enforce any and all rights granted hereunder or under such resolution or trust indenture, and may enforce and compel performance of all duties required by this act or by such resolution or trust indenture to be performed by the commission, or any officer thereof, including the fixing, charging and collecting of tolls for the use of the turnpike.
36 P.S. § 652n